The invention relates to a photographic camera, and more particularly, to a camera which permits a selection among a plurality of photographing modes including an automatic exposure mode, a manual exposure mode, an average photometry mode, a localized or spotwise photometry mode and the like.
As is well recognized, the photometry used in the conventional cameras can be categorized into an average photometry and a localized (or spotwise) photometry. The average photometry can be classified into a photometry averaged over the entire image field and another which is centrally emphasized, the latter being generally employed. Such average photometry produces a passable result for the typical object and over the localized photometry in respect of the ease of use, and accordingly, this average photometry is employed in most cameras.
The localized or spotwise photometry can be effectively used for an object having a high ratio of highlight and shadow when it is desired to control the exposure in accordance with the brightness of either the highlight or the shadow. However, it requires a troublesome operation and is likely to cause a photographing operation with an improper exposure. In the past, there has been a camera offered on the market which allows the photometry of only the central region of an image field, but this makes the photographic composition difficult. Accordingly, at the present time, cameras seldom adopt such a technique.
For the reasons mentioned above, the average photometry technique an excellent technique as compared with the localized or spotwise photometry when taking a picture of an ordinary object being photographed. However, in practice, objects being photographed are not limited to those having a reduced ratio of highlight and shadow, but include a number of objects having a greater ratio of highlight and shadow such as objects in the rear light, objects on a stage and objects in a composition which is formed when viewing the outdoors through a window. In particular, it is to be noted that the chance to take a picture of an object having a higher ratio of highlight and shadow increases as a photographer makes progress in his photographing skill. If an automatic exposure camera which operates on the basis of the average photometry is used to take a picture of an object having a high ratio of highlight and shadow, the exposure is controlled in accordance with the average brightness of the object, and hence prevents the intended composition of a photographer from being achieved when it is desired to control the exposure in accordance with the brightness level of a selected region of such object.
In the prior art practice, when taking a picture of such a special object, a so-called spot meter which utilizes a very limited angle for photometry is used to determine the brightness of an object being photographed at a plurality of locations. Based on the information representing the brightness of the object thus obtained and the intended composition to impart a proper exposure to a selected region and to determine the brightness level of the shadow, exposure factors such as a diaphragm aperture and an exposure period are determined, followed by taking a picture by manual operation of the camera. Where an object is accessible as when taking a picture in a studio, an incident-light exposure meter is used to determine the brightness of an object being photographed at a plurality of desired locations in order to determine exposure factors in the similar manner as mentioned above, thus allowing a picture to be taken by manual operation. However, the use of an exposure meter which is separate from the camera to perform the localized or spotwise photometry in order to determine the exposure factors requires a troublesome procedure, an increased length of time and a complex calculation, all of which represent disadvantages.
A so-called multi-mode camera is available in the prior art. This represents a camera which allows a selection among a plurality of photographing modes including an automatic and a manual exposure mode. However, such camera does not afford a display of adequate and full photographing information within a finder since such information varies from mode to mode.